Photo Credit: Dr_Microbe
The following is a summary of “Comparative emergence of maribavir and ganciclovir resistance in a randomized phase 3 clinical trial for treatment of Cytomegalovirus infection,” published in the September 2024 issue of Infectious Disease by Chou et al.
Researchers conducted a retrospective study to correlate the development of maribavir and ganciclovir resistance among patients receiving either drug for first-episode cytomegalovirus infection after a hematopoietic cell transplant, giving a response rate of 69.6% and 77.4%, respectively.
They analyzed viral mutations conferring drug resistance in plasma DNA extracts at baseline and post-treatment.
The results showed prior antiviral drug exposure was minimal, with only 2 cases of baseline drug resistance identified. A total of 241 individuals received either valganciclovir or maribavir for a minimum of 21 days (median 55-56 days). Drug resistance mutations emerged in 24 (10%) recipients of maribavir between 35-125 days (median 56) post-therapy initiation, including 12 of 14 who had a viral load rebound during treatment. Ganciclovir resistance mutations were found in 6 (2.5%) recipients of valganciclovir at 66-110 days (median 90), while 1 maribavir recipient exhibited a novel UL97 gene mutation (P-loop substitution G343A) that led to significant resistance to both maribavir and ganciclovir in vitro. Viral clearance was achieved in 17 (74%) of 23 patients with newly emerged maribavir resistance after re-treatment with a different CMV antiviral agent.
They concluded that maribavir resistance emerged earlier and more frequently than ganciclovir resistance after 3-8 weeks of therapy.
Source: academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiae469/7762822
